Explain Asynchronous Time Division Multiplexing in detail? Also discuss its advantages over synchronous TDM?

Explain Asynchronous Time Division Multiplexing in detail? Also discuss its advantages over synchronous TDM?

Asynchronous time-division multiplexing (ATDM) is a method of sending information that resembles normal TDM, except that time slots are allocated as needed dynamically rather than pre-assigned to specific transmitters. ATDM is more intelligent and has better bandwidth efficiency than TDM. asynchronous time-division multiplexing comprising receive circuits (CRl/i) supplying cells received via input links, transmit circuits (CTl/j) transmitting retransmitted cells on output links, a buffer memory (MT) storing the received cells and delivering the cells to be retransmitted and a buffer memory addressing device (SMT) including a write address source (SAE) and a read address source (fsl/j).

Advantages asynchronous TDM:
In asynchronous TDM, the timeslots are not fixed. They are assigned dynamically as needed. The objective would be to switch from one user to another user whenever the one user is idle, and to asynchronously time multiplex the data. With such an arrangement, each user would be granted access to the channel only when he has a message to transmit. This is known as an Asynchronous Time Division Multiplexing System (ATDM).
The crucial attributes of such a multiplexing technique are:

1. An address is required for each transmitted message, and 
2. Buffering is required to handle the random message arrivals.